# The effect of age and sex on T1, T2, and T2* relaxation time constants in cardiac MRI in healthy Finnish population

## TL;DR

This study establishes sex-specific reference values for T1, T2, and T2* relaxation times in cardiac MRI for a healthy Finnish population, finding higher values in females and no age-related changes.

## Contribution

The study provides new sex-specific reference values for T1, T2, and T2* in cardiac MRI for a healthy Finnish population.

## Key findings

- Females had higher T1 and T2 relaxation times than males.
- Age did not significantly affect T1, T2, or T2* values.
- No sex differences were observed in T2* relaxation times.

## Abstract

Magnetic resonance imaging (MRI) enables the non-invasive assessment of myocardial tissue properties through the T1, T2, and T2* relaxation mapping. Establishing population-specific normal reference values enhances diagnostic accuracy.

To study the effect of sex and age on the T1, T2, and T2* relaxation time constants in a healthy Finnish population.

We recruited 47 healthy volunteers aged 18–60 years from Eastern Finland from 2023 to 2024 and categorised them by sex and age (18–30 years, 31–41 years, and 42–60 years). The participants underwent a comprehensive screening process to eliminate the possibility of cardiac disease. MRI scans were conducted on 40 participants at 1.5 T. The T1, T2, and T2* relaxation time constants were calculated for basal, mid-ventricular, and apical short-axis slices.

The T1 and T2 relaxation time constants were higher in females than males (T1: 1040 ± 29 vs 1020 ± 17 ms, p < .01; T2: 51 ± 4 vs 48 ± 3 ms, p < .001). The 95% normal T1 range was 981–1098 ms for females and 985–1054 ms for males. The normal T2 range was 44–58 ms for females and 43–53 ms for males. No sex differences were found in the T2* relaxation times. The septal T2* across the whole population was 36 ± 7 ms (95% normal limit: 22–49 ms).

This study established age-independent and sex-specific reference values for the native myocardial T1, T2, and T2* relaxation time constants at 1.5 T. Females had higher T1 and T2 values than males, and age did not affect these values.